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41.
采用同步辐射能散X射线衍射技术,研究了高温高压下利用冲击波淬火技术制备的Zr41Ti14Cu12.5Ni10Be22.5大块金属玻璃的相演化过程。研究结果发现:在实验压力范围内,在不同压力下试样具有相同的初始析出相Zr2Be17,但是随后的相演化过程是不同的,根据应用压力的不同,试样的相演化过程可以分为3个不同的区域;另外,试样的晶化温度随着压力的增大而升高,但是在6.0 GPa存在一个突然的下降,在此压力点试样具有不同于其它压力点的相演化过程。相演化过程的不同和晶化温度的突然下降,可能归因于在不同压力下试样具有不同的原子构型。 相似文献
42.
由等温体积弹性模量的定义及其与压强关系的假设出发,导出了一个新的适用于高压下碱卤晶体的三参量等温状态方程。计算了室温下NaCl晶体在0~30 GPa压强范围内、CsCl晶体在0~40 GPa压强范围内的相对体积以及NaCl晶体在0~30 GPa压强范围内的等温体积弹性模量,计算结果与实验值一致。对等温体积弹性模量及其对压强的一阶、二阶导数与压强的关系进行了讨论,指出压强趋于无穷大时的等温体积弹性模量是常数。 相似文献
43.
通过分析现有文献,认为4种两参数的物态方程在高压物理研究中较为流行,它们是Vinet、Baonza、Morse和Born-Meyer(BM)方程。将这4种方程用于拟合50种材料的实验压缩数据,得出了零压下压缩模量及其一阶压力导数的优化取值,并计算了4种方程的平均压力误差。结果表明,Morse方程的精度最高,对50种材料的平均拟合误差为0.557 6%;BM方程次之,平均误差为0.615 1%;Vinet和Baonza方程的误差大一些,分别为0.788 9%和0.833 3%。对8种典型材料计算了压力误差随压强变化的曲线,所得结果与平均误差的趋势一致,也是Morse方程的精度最高。在宽广压力范围的高压物态方程研究中,推荐使用Morse方程。 相似文献
44.
Duygu Avci Lon J. Mathias Kevin Thigpen 《Journal of polymer science. Part A, Polymer chemistry》1996,34(15):3191-3201
Several new benzoate ester derivatives of ethyl α-hydroxymethylacrylate were synthesized using phase transfer catalysis and found to display unexpectedly rapid photopolymerization; i.e., from 2 to 8 times faster than MMA. New derivatives described here include the 4-fluoro-, 4-trifluoromethyl-, 4-methyl-, 2-hydroxy-, 4-nitro-, 4-methoxy-, 4-cyano-, and 3,4,5-trimethoxybenzoate esters along with the parent benzoate ester. Relative reactivities of these monomers in photopolymerizations were compared with those of the nonaromatic formate, acetate, hexanoate, and stearate derivatives. Reactivities of the nonaromatic ester derivatives increased with the length of the side chain while for the more reactive aromatic esters, rates increased in the order 4-methyl-, 4-fluoro- and benzoate < 4-trifluoromethyl- and 2-hydroxy- < 4-cyano- < 4-methoxy- < 3,4,5-trimethoxybenzoate. Tgs of the benzoate polymers ranged from 125°C for the 4-fluoro to 163°C for the 4-cyanobenzoate while those of the alkyl ester derivatives ranged from 15 to 78°C. Number average molecular weights of photoinitiated polymers (ca 10,000–20,000) were lower than those found for bulk and solution polymers (20,000—708,000) consistent with higher radical concentrations from photoinitiation. These materials greatly expand the number of candidates available for rapid photocure in thin film and coating applications, especially because their physical properties are those of linear rather than highly crosslinked structures formed from multifunctional systems. © 1996 John Wiley & Sons, Inc. 相似文献
45.
《Current Applied Physics》2020,20(1):49-57
In this work, we report a new method for extending the response spectra of organic photodetectors (OPDs) by incorporating PBDT-TT-C and PBDT-TT-F in the P3HT:PC61BM. The effects of PBDT-TT-C and PBDT-TT-F incorporation on the optical and electrical properties of OPDs were investigated, It was found that when the mass ratio of P3HT:PBDT-TT-F:PBDT-TT-C:PC61BM was 12:2:2:8, the response spectrum of the active layer was extended to 780 nm. The responsivity (R) and external quantum efficiency (EQE) of the OPDs reached 340, 376, 315 mA/W and 67%, 88%, 85% under 630, 530, and 460 nm illumination and −1 V bias, respectively, and the detectivity (D*) reached 1012 Jones. The results show that the inclusion of an appropriate amount of donor material with similar chemical structure and complementary absorption spectrum can reduce the influence of the doping material on the micro-morphology of the original film while improving the absorption of the spectrum. The interaction between the donor materials promotes the generation of photogenerated carriers and increases the photocurrent of the OPDs. In addition, the incorporation of the different component promotes crystallization of the film, resulting in a reduction in dark current of the OPDs. 相似文献
46.
A novel cross-linking process using two high molecular weight aromatic poly(thioether)s,which were synthesized by the reactions of 4,4′-thiobisbenzenethiol with 4,4′-difluorobenzophenone and 4,4′-difluorodiphenylsulfone,respectively, and commercially available lower molecular weight poly(p-phenylene sulfide)was investigated.These reactions were carried out in bulk by the addition of silver tetrafluroborate andα,α′-dibromo-p-xylene at 190℃over a period of 45 min. Furthermore,the same procedure could be modified to cross-link compression-molded films of these three polymers.The thermal and solubility behaviors of these polymers before and after cross-linking reactions,are presented. 相似文献
47.
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49.
S. V. Partsevskaya T. B. Zheltonozhskaya D. O. Klymchuk 《Molecular Crystals and Liquid Crystals》2018,671(1):128-139
AbstractA series of amphiphilic MOPEO-b-PCL copolymers (DBCs), based on biocompatible methoxypoly(ethylene oxide) with Mn=4.5?kDa and poly(ε-caprolactone) of a variable chain length, was synthesized by an anionic ring-opening block copolymerization. The structural investigations, performed by DSC and WAXS methods, revealed the microphase separation in DBC bulk structure and the existence of separate amorphous regions and microcrystalline domains of MOPEO and PCL blocks. Spectrophotometry and SLS were used to study the self-assembling of DBC macromolecules in selective dioxane/aqueous solution and to determine the main micellization parameters (CMC and -ΔG°). The DBC micelles morphology and their specific aggregation in mixed solvent were shown. 相似文献
50.